Web winding machines function to wind or roll up webs or films of material, such as a continuous length of plastic bags or a series of separate, interleaved or overlapping plastic bags. As the web advances on a conveyor belt toward a winder, its leading edge must be taken up upon a spindle to initiate the winding process. In one embodiment of a winding machine, multiple spindles are mounted on a rotatable turret. As the web is being wound upon one spindle, a second spindle stands by to take over the winding of the web once the amount of web material wound upon the first spindle reaches a predetermined maximum. Typically, when this happens, a web separator device causes the web to separate as it advances toward the winder, thus creating a leading edge in the new length of material to be wound. This leading edge must then be directed around the second spindle so that a new roll can be started.
Air horns are used to force the leading edge of the web onto the spindle upon which it will be wound. Existing air horns employ a single air tube to direct a blast of air between the conveyor belt and the spindle to lift the leading edge and direct it over the spindle. When attaching the leading edge to the spindle, the faster and more accurately the web can be attached, the straighter the edge of the roll of material will be. A fast and accurate attachment of the leading edge to the spindle will thus avoid or minimize the undesirable effect of telescoping of the roll.
Also, after the web has been started on the spindle, one embodiment of a winding machine will pivot the air horn away from the spindle and the turret will shift the spindle to a final wind position. As the web advances toward this spindle, it may have a tendency to lift off of the conveyor belt. This is especially a problem with interleaved bags; since the ends of the bags are not restrained, the bags may tend to separate before reaching the spindle, thus disrupting the final wind process.